Control mechanism for fuel injection device



Jan. 6, 1970 R. T. J. SKINNER 3,487,821

CONTROL MECHANISM FOR FUEL INJECTION DEVICE Filed April 12, 1968 //V. /V74P RIJ. SKINNER United States Patent U.S. Cl. 123-140 6 Claims ABSTRACT OF THE DISCLOSURE A control mechanism for a fuel injection device for an internal combustion engine comprising a fluid pressure operable device responsive to changes in inlet manifold pressure in the engine, a first lever connected to the device, a roller carried at the other end of the first lever, a first support block against which the roller engages, a control lever also engaging the roller and carrying a roller which engages with a further support block, the position of the control lever determining the quantity of fuel delivered to the engine, and control means connected to the control lever for moving it to vary the change in fuel delivery with movement of the first lever.

This invention relates to control mechanism for fuel injection devices for internal combustion engines, such control mechanisms being arranged to vary the quantity of fuel delivered to the engine.

The object of the present invention is to provide a control mechanism of the kind referred to in a convenient form.

According to the present invention a control mechanism for a fuel injection device for an internal combustion engine comprising, in combination, a housing, a fiuid pressure operable device mounted in the housing, said device being responsive to changes in inlet manifold pressure in an associated engine, a first lever connected at one end to said device and movable therewith, a roller carried at the other end of said first lever, 21 first support block in the housing against which the roller engages, a control lever also engaging said roller on the first lever, said control lever carrying a roller engaging with a further support block in the housing, the position of the control lever determining the quantity of fuel delivered to the engine, and control means connected to the control lever for moving it to vary the change in fuel delivery with movement of the first lever.

The invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a cross-sectional view of a control mechanism for a fuel injection dewce constructed in accordance with this invention,

FIGURE 2 is a similar view to FIGURE 1 showing modifications to the mechanism of that figure.

In an example of the invention there is provided a control mechanism for use in conjunction with a fuel (for instance petrol) injection device for an internal combustion engine. In ths example, the injection device is of a kind described and claimed in the complete specification of our copending British patent application No. 13800/ 64 which includes a distributor disc driven by the engine in a body for alternately supplying fuel to opposite ends of a cylindrical bore 12 containing a shuttle 13. The move ment of the shuttle 13 in the cylindrical bore 12 is limited by the position of a pair of plugs 14 and 15 respectively closing opposite ends of the cylindrical bore 12. The control mechanism of the present invention is connected to the body 11 and is arranged to adjust the position of one of the plugs, namely the plug 15 in the cylindrical bore 12, in accordance with changes in induction manifold pressure in the engine with which the device is associated.

This mechanism shown in FIGURE 1 comprises a housing 40 having an inlet 41 for communication with the inlet manifold of the engine and having the plug 15 of the injection device extending into its interior. One end of the housing 40 contains a bellows 42 loaded by a spring 43. This bellows 42 is subjected to the manifold pressure within the housing and the support assembly for it is movable against the spring 43 so that a co-axial arm 44 carried by the bellows at one of its ends is movable in response to atmospheric pressure, (as will be described), as Well as manifold pressure. To the opposite end of the arm of the arm 44 is pivotally connected at 45 a first lever 46 which, at its end, remote from the arm 44, carries a roller 47. The roller 47 is engaged at opposite sides by a support block 48 and by a control lever 49 respectively. The support block 48 is mounted on screws 50, 51 so as to be adjustable relatively to the housing 40 and the support block 48 has a profiled surface which the roller 47 can engage. The ends of the support block 48 can be adjusted independently by the screws 50 and 51 relative to the housing towards and away from the first lever 46.

A second block 52 is mounted on two screws 53, 54 on the opposite interior wall of the housing 40 and is thus also adjustable at both ends relative to the housing 40. However, the second block 52 has a flat surface which is engaged by a roller 55 on one end of the previously mentioned control lever 49 which, near its other end, engages the plug 15 of the injection device. Between the plug 15 and the roller 55 and on the opposite side of the control lever 49 from the former, this lever is engaged by the roller 47 of the first lever 467 The axle 56 of the roller 55 of the control lever 49 also carries a link 57 connected to a manual or automatic contol through a lever 58 and spindle 59, this link 57 being thus pivoted about the axle 56 of the roller 55 relatively to the control lever 49. Engaging with the control lever 49 on the opposite side from the plug 15, there is a plunger 60 disposed in a recess 61 in the housing 40, which is retracted into this recess 61 as the control lever 49 is moved to permit the plug 15 to move into the housing 40 to increase the fuel supply to the engine.

The shape of the roller engaging face of the first support block 48 is such that the desired response of the mechanism is achieved. As the roller 47 moves, under the influence of decreasing manifold pressure, for instance under overrun conditions, to the limit of its permitted travel, the slope of this surface of the block 48 is sharply increased thus sharply moving the control lever 49 which, in turn, moves the plug 15 substantially to reduce the supply of fuel to the engine.

It will be apparent that, in normal operation, the roller 47 of the first lever 46 moves along the control lever 49 to vary the position of the plug 15, but that the mechanical advantage can be varied by altering the inclination of the control lever 49 in relation to the slope of the surface of the first support block 48. This alteration is accomplished by moving the roller 55 of the control lever 49 along the surface of the second block 52, by means of the link 57 and control lever 58. Further changes can be introduced by this movement, these changes being governed by the position and shape of the surface of the second block 52.

The provision for adjustments of the blocks 48 and 52 enables the characteristic response of the mechanism to be adjusted to suit differing engine characteristics and other requirements. The dotted positions of the parts 46, 47, 49, 55, 57, 58 and 59 show the conditions for warming up, these conditions being settable manually.

The mechanism is also responsive to changes in atmospheric pressures, due for example to altitude changes. This is achieved by permitting air at atmospheric pressure to reach one end of the bellows 42, the manifold pressure acting upon the other end of the bellows 42, the air displaced by compression of the bellows 42 being permitted to escape to atmosphere through the hole 62, and the end of the housing being sealed by the rolling diaphragm 63.

The construction shown in FIGURE 2 includes a manually adjustable knob 64 for controlling the position of the arm 65 which is the equivalent of the arm 44 in FIGURE 1 in relaion to a spring loaded member 66 which moves in response to changes in manifold pressure, and which is sealed by a rolling diaphragm 67, this knob 64 being preset to control the response of the mechanism to correspond to a predominating atmospheric pressure.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A control mechanism for a fuel injection device for an internal combustion engine comprising, in combination, a housing, a fluid pressure operable device mounted in the housing, said device being responsive to change in inlet manifold pressure in an associated engine, a first lever connected at one end to said device and movable therewith, a roller carried at the other end of said lever, a first support block adjustably mounted in the housing against which the roller engages, a control lever also engaging said roller on the first lever, said control lever carrying a roller engaging with a further support block adjustably mounted in the housing, the position of the control lever determining the quantity of fuel delivered to the engine, and control means connected to the control lever for moving it to vary the change in fuel delivery with movement of the first lever.

2. A control mechanism as claimed in claim 1 in which the first support block has an inclined face and movement of the roller along it varies the position of the control lever and thus varies the quantity of fuel delivered to the engine, adjustment of said support block varying the inclination of said face.

3. A control mechanism as claimed in claim 1 in which the further support block has an inclined face and the movement of the control lever along it is arranged to vary the quantity of fuel delivered to the engine, adjustment of said support block varying the inclination of said face.

4. A control mechanism according to claim 1 in which a movable arm in the body is arranged to control longitudinal movement of the control lever.

5. A control mechanism according to claim 1 in which the fluid pressure responsive device is also responsive to atmospheric pressures so that the response of the device to manifold pressure is modified in accordance with changes in atmospheric pressure.

6. A control mechanism according to claim 1 in which the first support block is so shaped that when the roller on the first lever moves beyond a predetermined position on said support block, angular movement of the control lever takes place to cause substantial reduction in the supply of fuel to the engine.

References Cited UNITED STATES PATENTS 2,984,232 5/1961 Arndt et al. 123--140.3 3,103,211 9/1963 Cameron 123140.2 3,354,876 11/1967 Durham 123140.2 3,394,685 7/1968 Downing 123l39 XR LAURENCE M. GOODRIDGE, Primary Examiner US. Cl. X.R. l23ll9 

